I've installed NetBeans and Eclipse in Windows, Mac and Linux and, though NetBeans and Eclipse UI performance is quite similar in Windows and Mac, in Linux I find NetBeans evidently slower than Eclipse. Do not know if Swing does some hardware acceleration in Linux, but in my Linux box, it does not perform as well as in Windows or Mac.

What UI are you using for Swing? The GTK look and feel is very slow, as Java is forced to work around GTK's lack of transparency by drawing each widget twice, once on a black background and once on a white background, then downloading the images from the X server, mixing them to recover the transparency, and finally uploading the recovered image.